CVE-2007-3957 in xserver
Summary
by MITRE
Buffer overflow in Nipun Jain xserver 0.1 alpha allows remote attackers to cause a denial of service via a POST request with a long URI.
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Analysis
by VulDB Data Team • 09/28/2024
The vulnerability identified as CVE-2007-3957 represents a critical buffer overflow flaw within the xserver software version 0.1 alpha developed by Nipun Jain. This issue manifests specifically when the server processes HTTP POST requests containing excessively long URIs, creating a condition where memory boundaries are exceeded during request handling. The vulnerability operates at the application layer of the network stack, affecting web server implementations that utilize this particular xserver component for processing HTTP traffic.
The technical mechanism behind this buffer overflow involves improper input validation and boundary checking within the URI parsing routine of the xserver application. When a remote attacker submits a POST request containing a URI that exceeds the predetermined buffer size allocated for URI storage, the excess data overflows into adjacent memory locations. This overflow can corrupt critical program data structures, leading to unpredictable behavior and ultimately resulting in application termination. The flaw demonstrates characteristics consistent with CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory regions.
The operational impact of this vulnerability extends beyond simple denial of service, as it provides attackers with the capability to disrupt legitimate service availability for users accessing the affected web server. Remote exploitation requires no authentication credentials, making the attack surface particularly wide and accessible. The vulnerability affects systems where the vulnerable xserver version is deployed as a web server component, potentially impacting organizations relying on this specific software stack for their web hosting infrastructure. The consequences include complete service disruption, requiring system restarts and manual intervention to restore normal operations, while also potentially exposing underlying system vulnerabilities through memory corruption artifacts.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. The primary recommendation involves upgrading to a patched version of the xserver software that implements proper input validation and bounds checking for URI handling. Organizations should implement network-level controls such as rate limiting and URI length restrictions at proxy servers or load balancers to prevent malformed requests from reaching the vulnerable server. Additionally, deploying intrusion detection systems capable of identifying suspicious POST request patterns with excessively long URIs can provide early warning of attempted exploitation. From a defensive standpoint, the vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and organizations should consider implementing comprehensive network segmentation and access control policies to limit the potential impact of such attacks. Regular security assessments and vulnerability scanning should be conducted to identify similar buffer overflow conditions within the broader application ecosystem, as this represents a common class of vulnerability that affects numerous web server implementations across different platforms and technologies.